TNF and infection: Several authors have tried to correlate CMV and IBD, hypothesizing the following: possible triggering of CMV infection at the onset of IBD [11], [12]; a worsening of the infection [13], [14], [15], [16]; an association between the use of anti TNF-alpha and a higher risk of CMV disease [17], [18]; or the higher prevalence of CMV disease in UC patients, compared with CD [19], [20].